1. Field of the Invention
The invention relates to an automation system comprising a first controller and a second controller which are connected to an input device via a field bus, where the input device is particularly configured to operate, for example, in an automation system having a field bus compliant with the Profinet IO standard.
2. Description of the Related Art
In general, automation systems having input devices are generally known, and are preferably used in process and production automation to receive data and forward it to relevant controllers, such as automation devices of the programmable logic controller type, at distributed locations in the process to be automated.
In distributed automation environments, a status and a signal image of the process signals of the input devices are frequently required for different controllers.
To distribute the process signal image to a first controller and to another second controller, the solution has hitherto been for the data from the input device or peripheral to be read by the first controller and then preferably transmitted or forwarded via a separate data line to the second controller which likewise requires these process signals for performing its specific control tasks. The disadvantage of this procedure is that the data, i.e., the process signals, reaches the second controller with a delay compared to the arrival time at the first controller. This forwarding must also be configured, i.e., programmed, which involves higher cost/complexity. Also, diagnostic information would likewise have to be communicated to possible other controllers via this additional data path. Data consistency between the different controllers is not therefore guaranteed.